The research plan is to continue at the molecular and genetic level an investigation of the regulation of two glycoproteins crucial to Dictyostelium development. One is a cAMP phosphodiesterase, which is induced by cAMP, and the other is an inhibitor of the phosphodiesterase, which is repressed by cAMP. The point of departure for the project is the cloning of both genes. Translational studies on the regulation of their mRNAs have already been done. Cloned genes will be used to determine structure, to assay mRNA production, and for comparison with other similarly or differently regulated genes. The role of cAMP binding proteins and protein kinases in Dictyostelium development will be determined by examining a novel class of cAMP sensitive mutations previously made in this laboratory. Structural gene mutations of the proteins will be isolate and used to select secondary mutations. Improvements in the genetic manipulation of Dictyostelium will be made. Developmentally regulated genes will be selected by complementation of yeast auxotrophs, as we have already done with URA1